Grassy Island is a small, uninhabited 72-acre (29 ha) American island in the Detroit River. It is located just north of Grosse Ile and west of Fighting Island, about 600 feet (180 m) west of the Canada–United States border. The island is part of the city of Wyandotte, in Wayne County. The island is part of the Detroit River International Wildlife Refuge. Grassy Island should not be confused with Grass Island, which is an island of Ontario on the exact opposite side of the Detroit River.